1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
#include "qwasmopenglcontext.h"
#include "qwasmoffscreensurface.h"
#include "qwasmintegration.h"
#include <EGL/egl.h>
#include <emscripten/bind.h>
#include <emscripten/val.h>
namespace {
void qtDoNothing(emscripten::val) { }
} // namespace
EMSCRIPTEN_BINDINGS(qwasmopenglcontext)
{
function("qtDoNothing", &qtDoNothing);
}
QT_BEGIN_NAMESPACE
QHash<QPlatformSurface *, EMSCRIPTEN_WEBGL_CONTEXT_HANDLE> QWasmOpenGLContext::s_contexts;
QWasmOpenGLContext::QWasmOpenGLContext(QOpenGLContext *context)
: m_actualFormat(context->format())
{
m_actualFormat.setRenderableType(QSurfaceFormat::OpenGLES);
// if we set one, we need to set the other as well since in webgl, these are tied together
if (m_actualFormat.depthBufferSize() < 0 && m_actualFormat.stencilBufferSize() > 0)
m_actualFormat.setDepthBufferSize(16);
if (m_actualFormat.stencilBufferSize() < 0 && m_actualFormat.depthBufferSize() > 0)
m_actualFormat.setStencilBufferSize(8);
}
QWasmOpenGLContext::~QWasmOpenGLContext()
{
destroyWebGLContext(m_contextOwningSurface);
}
bool QWasmOpenGLContext::isOpenGLVersionSupported(QSurfaceFormat format)
{
// Version check: support WebGL 1 and 2:
// (ES) 2.0 -> WebGL 1.0
// (ES) 3.0 -> WebGL 2.0
// [we don't expect that new WebGL versions will be created]
return ((format.majorVersion() == 2 && format.minorVersion() == 0) ||
(format.majorVersion() == 3 && format.minorVersion() == 0));
}
void QWasmOpenGLContext::destroyWebGLContext(QPlatformSurface *surface)
{
if (surface == nullptr)
return;
int context = s_contexts.take(surface);
if (context)
destroyWebGLContext(context);
}
void QWasmOpenGLContext::destroyWebGLContext(EMSCRIPTEN_WEBGL_CONTEXT_HANDLE contextHandle)
{
if (!contextHandle)
return;
// Destroy GL context. Work around bug in emscripten_webgl_destroy_context
// which removes all event handlers on the canvas by temporarily replacing the function
// that does the removal with a function that does nothing.
emscripten::val jsEvents = emscripten::val::module_property("JSEvents");
emscripten::val savedRemoveAllHandlersOnTargetFunction = jsEvents["removeAllHandlersOnTarget"];
jsEvents.set("removeAllHandlersOnTarget", emscripten::val::module_property("qtDoNothing"));
emscripten_webgl_destroy_context(contextHandle);
jsEvents.set("removeAllHandlersOnTarget", savedRemoveAllHandlersOnTargetFunction);
}
EMSCRIPTEN_WEBGL_CONTEXT_HANDLE QWasmOpenGLContext::createEmscriptenContext(const std::string &canvasSelector,
QSurfaceFormat format)
{
EmscriptenWebGLContextAttributes attributes;
emscripten_webgl_init_context_attributes(&attributes); // Populate with default attributes
attributes.powerPreference = EM_WEBGL_POWER_PREFERENCE_HIGH_PERFORMANCE;
attributes.failIfMajorPerformanceCaveat = false;
attributes.antialias = true;
attributes.enableExtensionsByDefault = true;
attributes.majorVersion = 2; // try highest supported version ES3.0 / WebGL 2.0
attributes.minorVersion = 0; // emscripten only supports minor version 0
// WebGL doesn't allow separate attach buffers to STENCIL_ATTACHMENT and DEPTH_ATTACHMENT
// we need both or none
const bool useDepthStencil = (format.depthBufferSize() > 0 || format.stencilBufferSize() > 0);
// WebGL offers enable/disable control but not size control for these
attributes.alpha = format.alphaBufferSize() > 0;
attributes.depth = useDepthStencil;
attributes.stencil = useDepthStencil;
EMSCRIPTEN_RESULT contextResult = emscripten_webgl_create_context(canvasSelector.c_str(), &attributes);
if (contextResult <= 0) {
// fallback to opengles2/webgl1
// for devices that do not support opengles3/webgl2
attributes.majorVersion = 1;
contextResult = emscripten_webgl_create_context(canvasSelector.c_str(), &attributes);
}
if (contextResult <= 0) {
qWarning() << "WebGL context creation failed";
return contextResult;
}
// Sync up actual format
EmscriptenWebGLContextAttributes actualAttributes;
EMSCRIPTEN_RESULT attributesResult = emscripten_webgl_get_context_attributes(contextResult, &actualAttributes);
if (attributesResult == EMSCRIPTEN_RESULT_SUCCESS) {
if (actualAttributes.majorVersion == 1) {
m_actualFormat.setMajorVersion(2);
} else if (actualAttributes.majorVersion == 2) {
m_actualFormat.setMajorVersion(3);
}
m_actualFormat.setMinorVersion(0);
}
return contextResult;
}
QSurfaceFormat QWasmOpenGLContext::format() const
{
return m_actualFormat;
}
GLuint QWasmOpenGLContext::defaultFramebufferObject(QPlatformSurface *surface) const
{
return QPlatformOpenGLContext::defaultFramebufferObject(surface);
}
bool QWasmOpenGLContext::makeCurrent(QPlatformSurface *surface)
{
// Record this makeCurrent() attempt, since isValid() must repeat the answer
// from this function in order to signal context loss to calling code.
m_madeCurrentSurface = surface;
// The native webgl context is tied to a single surface, and can't
// be made current for a different surface.
if (m_contextOwningSurface && m_contextOwningSurface != surface)
return false;
// Return existing context or crate a new one.
EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context;
if (m_contextOwningSurface && s_contexts.contains(m_contextOwningSurface)) {
context = s_contexts.value(surface);
} else {
m_contextOwningSurface = surface;
bool isOffscreen = surface->surface()->surfaceClass() == QSurface::Offscreen;
auto canvasId = isOffscreen ? static_cast<QWasmOffscreenSurface *>(surface)->id() :
static_cast<QWasmWindow *>(surface)->canvasSelector();
context = createEmscriptenContext(canvasId, m_actualFormat);
s_contexts.insert(surface, context);
}
if (context == 0)
return false;
return emscripten_webgl_make_context_current(context) == EMSCRIPTEN_RESULT_SUCCESS;
}
void QWasmOpenGLContext::swapBuffers(QPlatformSurface *surface)
{
Q_UNUSED(surface);
// No swapbuffers on WebGl
}
void QWasmOpenGLContext::doneCurrent()
{
m_madeCurrentSurface = nullptr;
}
bool QWasmOpenGLContext::isSharing() const
{
// Return false to signal that context sharing is not supported.
// This will in turn make QOpenGLContext::shareContext() return
// a null context to the application.
return false;
}
bool QWasmOpenGLContext::isValid() const
{
if (!isOpenGLVersionSupported(m_actualFormat))
return false;
// We get isValid() calls before we see the surface and are able to
// create a native context, which means that "no context" is a valid state.
if (!m_madeCurrentSurface && !m_contextOwningSurface)
return true;
// Can't use this context for a different surface, since the native
// webgl context is tied to a single canvas.
if (m_madeCurrentSurface != m_contextOwningSurface)
return false;
// If the owning surfce/canvas has been deleted then this context is invalid
if (!s_contexts.contains(m_contextOwningSurface))
return false;
return !emscripten_is_webgl_context_lost(s_contexts.value(m_contextOwningSurface));
}
QFunctionPointer QWasmOpenGLContext::getProcAddress(const char *procName)
{
return reinterpret_cast<QFunctionPointer>(eglGetProcAddress(procName));
}
QT_END_NAMESPACE
|
